Viruses, bacteria, and prions are sometimes dangerous, but they can also do some good. These three microorganisms have some similarities and some differences. These microorganisms or organic particles range in size from prions being the smallest to bacteria usually being the biggest. These microorganisms are capable of more than you might think.
Although viruses are responsible for many diseases, it has been debated whether or not they are organisms based of how the reproduce, which they do so by manipulating a host species. The general structure of viruses includes a polygonal capsid, spikes, and an envelope around the DNA. The capsid surrounds the nucleic acid and the spike are the receptors. These receptors are host specific. Viruses can effect humans, animals, plants, and bacteria.
The reproduction cycles for viruses are the lytic cycle and the lysogenic cycle. In the lytic cycle there is attachment, when the virus’ receptor combines with the host, penetration, when the DNA is injected into the host cell, biosynthesis, when the virus takes over the host cells functions and makes it replicate the viral DNA and manufacture the capsids, maturation, when the DNA and capsids are assembled, and release, when the fully formed capsids are released into the host organism to infect more host cells.
HIV, the flu, and the common cold are examples of diseases caused by viruses. HIV is caused by a retrovirus that goes through the lysogenic cycle. The lysogenic cycle is when the virus is latent and waits for conditions to be right before it becomes active and starts affecting its host. Also in the lysogenic cycle viral DNA is integrated with the host DNA making it harder to be recognized and destroyed by the host on future encounters. The ...
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As of now, the functional roles of prions remain an enigma, with the exact functional role not being known. There have been several attempts to try and understand the physiological functions of the prion protein. One way of trying to deduce the functions would be to see which other proteins would interact with PrP, and some of the interactors would be key components of physiolo...
The word virus comes from the Latin word, poison. A virus infects a cell and into it, inserts its DNA. The virus then multiplies inside the cell and when enough of the virus has been produced, the newly formed viruses will break out into the body of the host, destroying the cell in the process. Variola major and Variol...
A prion is a disease-carrying agent that is composed entirely of proteins. It is the cause of
Viruses are the simplest and tiniest of microbes, and are made up of proteins, nucleic acid, and lipids. The nucleic acids contain the genetic code that helps them grow and reproduce, but only once they find their way into a living organism. Viruses themselves are not considered living organisms because they don’t have cells, they don’t metabolize nutrients, produce and excrete wastes, and they can’t move around on their own. The remains of the nucleic acid then forms a covering, called the capsid. Once the capsid gets removed, viruses use the building materials of th...
The virus is primarily spherical shaped and roughly 200nm in size, surrounded by a host-cell derived membrane. Its genome is minus-sense single-stranded RNA 16-18 kb in length. It contains matrix protein inside the envelope, hemagglutinin and neuraminidase, fusion protein, nucleocapsid protein, and L and P proteins to form the RNA polymerase. The host-cell receptors on the outside are hemagglutinin and neuraminidase. The virus is allowed to enter the cell when the hemagglutinin/ neuraminidase glycoproteins fuse with the sialic acid on the surface of the host cell, and the capsid enters the cytoplasm. The infected cells express the fusion protein from the virus, and this links the host cells together to create syncitia.
On a closing note, prion research is significant not only for possible breakthroughs in understanding TSEs, but because of the vast implications the very concept of prions holds for the entire field of biology. As the first substance discovered that can replicate in the absence of nucleic acids, prions defy one of the most central biological doctrines. The similarities between TSEs and dementia disorders like Alzheimer’s disease and “findings of proteins with a prion-like behavior in yeast and other fungi” (Soto, 2006, 143) suggest that prions and proteins like them may be much more common than ever expected (Soto, 2006, 154).
Human Immunodeficiency Virus, in short, called HIV is a virus that attacks and weakens your immune system, which can later lead to the fatal stage known as Acquired Immunodeficiency Syndrome (AIDS). Many people are uninformed of exactly how HIV is transmitted, but the most common route of transmission is through unprotected sexual intercourse. This is because body fluids such as semen that are infected with the HIV virus can enter another person’s body thus spreading the virus. Other routes of transmission include: infected mother to baby and sharing needles with an infected person (Centers for Disease control, 2001). Once the virus enters your body, it looks for it’s favorite cell, the T-cell, attaches its CD4 receptor to the CD4 cell (T-cell) and begins infecting the cell. In order for viruses to replicate they will have to hijack the T-cells, make viral cells, and then infect the rest of the cells in your body. After the virus has entered the T-cell, the T-cell will read it and order the cell to make more virus genes. Next, the cell begins to make virus capsids and genes; this is where all viral parts of the virus cells are made. The cell then begins to assemble the virus and after that the cell bursts open releasing the virus cells to start infecting the other cells (Phelan, 2010).
Viruses are important to discuss because they are analyzed in almost all microbiology classes. Viruses can be characterized as, “any of a group of submicroscopic entities consisting of a single nucleic acid chain surrounded by a protein coat and capable of replication only within the cells of living organisms” (Biology). Bacteriophage are more specific in a sense that they are “a virus that infects and replicates within a bacterium” not just any living organisms cells (Biology). These viruses can replicate in 2 different cycles: lytic cycle or the lysogenic cycle. If a virus takes enters the lytic cycle it will cause infection and destruction of the host cell. This is done when the virus first penetrates the cell membrane of the host cell.
Looking at Prions and Viroid’s to understand them may be difficult. Because of their simplified structures both prions and viroids are sometimes called subviral particles. It is very simple to get confused between the two at some points. A viroid (an infectious RNA molecule) is like a virus but not quite the same thing. It's smaller than a virus and has no capsid. Prions on the other hand have neither DNA nor RNA to transmit infection. Not enough is known about them, but we do know that a prion is an abnormal or mutated form of a usually harmless protein. They work in two different fields one might say, one mainly on plant life and other on the rest around like animals.
The structures of all three of these subjects are very different. Bacteria have three different shapes known as strepocolli, which are chains of cocci that are spherical or oval shaped. Escherichia coli that lives in your intestines and are rod shaped. And vibrio’s that are spiral shaped. In bacteria, DNA and RNA are floating in the cytoplasm. Bacteria have a cell wall, a cell membrane, flagella, and ribosomes but do not have a nucleus. Viruses are sub-microscopic particle, about 20-300 nanometers. They have two main parts: a capsid which is composed of protein subunits and an inner core of nucleic acid, either DNA or RNA. They also have spikes made from a glycoprotein. Viruses have no cell wall, but they have a protein coat instead. They don’t have a nucleus also. Last but not least, prions: the normal protein prions are bounded to sur...
Prokaryotes are divided into eubacteria and archaebacteria. Eubacteria are considered bacteria, and will be henceforth referred to as such. Archaebacteria lived in more extreme environments, are older than eubacteria, and have sufficient chemical differences to be distinct from bacteria. Prokaryotes are unicellular organisms that reproduce through fission and conjugation, have great metabolic diversity, have a single chromosome arranged in a circle called a plasmid with no nuclear membrane, and tend to have cell walls. One of the most notable characteristics is the lack of membrane-bound organelles, such as lysosomes or the endoplasmic reticulum. Bacteria have three types of shapes: coccus, bacillus, and spirillum (Starr, C., et al, 2004). Cocci are sphere-like and are around .5 to 1 µm long, bacilli are rod-like and 0.5-1.0 µm wide by 1.0-4.0 µm long, and spirilli are spiral-shaped and vary from 1 µm to over 100 µm in length (Elert, G, 2006.) Designations of this type may be made more precise through addition of morphemes to the front of the word, such as in the case of diplococcus, which means a pair of spherical bacteria. Gram-negative bacteria have an additional coating beyond the cell wall, called a capsule. These capsules have lipopolysaccharide in them, which is toxic and caus...
The word virus is derived from the Latin word meaning “poison, slimy liquid, or poison juice. ” Viruses are very small infectious (pathogenic) particles that cannot be seen with an ordinary lighted microscope. The virus is encapsulated with protein, and is unable to multiply unless it is living inside the cells of a living host. As such, when a virus enters the living cells of an animal or plant, something extraordinary
After contacting a host cell, a virus will insert genetic material into the host and take over that host 's functions. The cell, now infected, continues to reproduce, but it reproduces more viral protein and genetic material instead of its usual products. It is this process that earns viruses the classification of "parasite".
Kent, M., 2013. Bacteria . In: Advanced Biology . s.l.:Oxford University Press , p. 366.